Detectives investigating a major crime have narrowed down their suspect pool to a few individuals, but can’t hunker down on the actual perpetrators. Or, a relationship is teetering on the brink due to persistent claims of infidelity, yet there’s no definite way to validate the allegations.
In such scenarios, polygraph exams can bridge the gap between truth and suspicion.
Administering polygraph evaluations enables law enforcement officers to catch criminal suspects in a lie, providing a pathway to conclusive investigations. The tests are also used in addiction treatment programs to track the progress among recovering addicts, in relationship counseling to restore broken trust, and as part of post-conviction offender monitoring.
Read below for more insights into how polygraph tests can provide reliable conclusions in investigative processes.
Exploring the Science Behind Lie Detector Tests
Polygraphs are based on the fact that lying activates the Autonomic Nervous System (ANS).
ANS is a part of the Central Nervous System (CNS) that regulates various physiological responses, including skin conductance, heart rate, and breathing patterns.
Whenever a person lies during a lie detector test, their answers trigger significant elevations in ANS-regulated physiological responses. This enables polygraphers to make deductions of truthfulness or deception, with varying accuracy depending on the test quality.
How Lie Detector Tests Bridge the Gap Between Doubt and Proof
Not all criminal investigations proceed to their logical end. Where detectives have narrowed down to a few suspects but the trail has run cold, administering a polygraph can help break the case wide open.
Lie detector tests enable detectives to corroborate or impeach suspect statements.
A professional examiner will administer a series of polygraph questions relevant to the subject under investigation. Glaring inconsistencies, coupled with significant signs of ANS arousal, are then used to infer deception.
Other ways polygraph findings may resolve suspicions include:
1. Validating Disclosure Statements
A couple undergoing relationship counseling may submit to a lie detector test to resolve their relationship disputes.
Usually, the betraying partner undergoes a polygraph exam to confirm the authenticity of their disclosure statement. It’s a significant step towards allaying doubts and kick-starting the healing process.
2. Investigating Post-Offender Misconduct Allegations
Following their release from incarceration, sex offenders are closely monitored to ensure they pose no threats to the community.
Findings from polygraph exams may help probation officers to investigate misconduct allegations and recommend appropriate action.
3. Investigating Workplace Theft
Companies lose billions to employee theft annually.
Where evidence points to specific employees, polygraph tests can play a significant role in nailing the actual suspects.
Case Study on the Role of Lie Detector Tests in Validating Allegations
The Weleetka Murders in Oklahoma exemplify the role of polygraphs in bridging the gap between truth and suspicion.
Just when the case threatened to go cold, law enforcement officers decided to polygraph Kevin Sweat, a prime suspect in the murder of his fiancée, Ashley Taylor.
Not only did Sweat fail the lie detector test, but his response also enabled detectives to find the deceased’s remains and connect him to another murder, leading to his eventual conviction.
Significance of Caution While Administering Lie Detector Tests
Not every case can be broken by lie detector tests. Often, these exams have resulted in false positives and false negatives.
Numerous factors may cause an examinee to fail a lie detector test, including improper question design and the use of countermeasures during the in-test phase.
To perform reliable polygraph tests, it’s imperative to enlist polygraphers with a wealth of practical industry experience. Insist on someone who graduated from an American Polygraph Association (APA)-accredited school and has practiced consistently for at least five years.
It’s also best to choose an examiner specializing in the type of testing you plan to undergo. For instance, many law enforcement polygraphers focus on proving that a suspect is guilty of the accusations. Such examiners may be unideal in relationship counseling, where reconciliation is the primary focus.
Using Lie Detector Test Findings as Secondary Evidence
Polygraph reports should never be used for probative purposes. Instead, they’re strictly meant to support other pieces of evidence.
That very reason makes lie detector tests inadmissible in many jurisdictions, in and of themselves. In exceptional circumstances like the Weleetka Murders, the test findings are only admissible where an individual’s credibility has been severely attacked by other evidence.
Consent and adequate preparation are other grounds for polygraph admissibility. Unless an examinee was taken through preliminary interviews several weeks ahead of the actual test, and they willfully submitted to being polygraphed, then findings from lie detector tests are deemed invalid.
Leveraging Polygraph Findings to Validate Allegations
Lie detector tests have long been used to sift truth from suspicion. Detectives can use polygraph findings to expedite investigative processes by shrinking their suspect pool.
Lie detector tests are also an invaluable tool in therapeutic settings. They enable therapists to verify the authenticity of disclosure statements, assess the efficacy of a treatment program, and rebuild broken trust.
In post-conviction offender testing, polygraphs can help probation officers to investigate alleged parole violations and assess reoffending risks.
